Vaccinia immune globulin: A blood product rich in antibodies against vaccinia, the virus in the smallpox vaccine. Vaccinia immune globulin (VIG) is the only known antidote to the complications of vaccination. It is derived from the blood of people who have been vaccinated recently, usually within the past 2 months. VIG is believed to be used against some but not all of the complications. namely extensive accidental implantation, eczema vaccinatum, severe or recurrent generalized vaccinia, and progressive vaccinia
Studies in the 1950's and 60's indicated that the complications of vaccination occurred soon after vaccination and before significant antibody could be detected in the blood. As a result, the late Dr. Henry Kempe and others developed the concept of providing antibody in the form of gamma globulin. Empiric evidence appeared to demonstrate that patients healed when VIG was administered for certain complications. Vaccination and the occurrence of complications ceased in the early 1970's and no definitive studies were carried out to determine the exact efficacy of VIG.